1. Field
Aspects of the present invention relate to a liquid crystal display device, and more particularly, to a liquid crystal display device with a built in touch screen, having a panel in which a light sensor is provided.
2. Description of the Related Art
A touch screen is provided on a top surface of an image display device so that instruction contents displayed on the screen of the image display device can be selected using a human hand or an object. The touch screen is contacted directly by the human hand and/or the object. Therethrough, the touch screen determines a contact position and the image display device receives the instruction contents corresponding to the contact position as input signals to be driven according to the input signals.
The image display device having the touch screen does not require a separate input device connected to the image display device in order to be operated, such as a keyboard and a mouse, thus, the usage thereof tends to increase.
Recently, the touch screen is also used in a liquid crystal display device. The liquid crystal display device with the touch screen includes a liquid crystal display panel that displays an image and a touch screen panel that is provided on the top side of the liquid crystal display panel in order to receive a predetermined input from a user and to detect position information.
At this time, in order to position the touch screen panel on the top side of the liquid crystal display panel, a frame having an air layer between the liquid crystal display panel and the touch screen or adhesive is used. However, in this case, a layer having different refractive index from refractive index of the liquid crystal display panel and the touch screen panel is generated between the liquid crystal display panel and the touch screen panel, and thus, the optical characteristics of the liquid crystal display device are degraded.
Consequently, a separate touch screen panel is manufactured and attached to the liquid crystal display panel, and has disadvantages including increased manufacturing costs and increased thickness of the liquid crystal display device.